How Much Geologic Hydrogen Is Recoverable?

Estimated reading time: 6 minutes · Last updated: 2026-08-18

Geologic hydrogen is hydrogen generated underground by water‑rock reactions or radioactive decay and can emerge naturally through boreholes and mine vents. Field results vary: at Kidd Creek, 35 long‑term boreholes averaged 8 kilograms of H2 per year and, extrapolated across the mine’s more than 14,000 boreholes, researchers report roughly 140 metric tons per year; a stimulated test in Oman used a one‑kilometer borehole and 50,000 cubic meters of injected water and produced gas that was 90% hydrogen. As first reported by MIT Technology Review, these measurements show that recoverable H2 exists in situ, but no commercially viable reservoir has yet been demonstrated and key datasets remain unpublished.

If we can set some smart minds into figuring out how to hook it up and use it, then we’ve got a win for this nascent economy.

Barbara Sherwood Lollar, University of Toronto

Where geologic hydrogen comes from and how much there might be

Geologic hydrogen forms when water reacts with iron‑rich minerals or when radioactive decay alters subsurface chemistry; microbes then use that H2 as an energy source in some deep brines. The US Geological Survey has estimated that the crust produces hydrogen in quantities described as "trillions of tons of H2," a volume that, if even a small fraction were accessible, could meet demand for centuries. Published field studies supply the only ground truth so far: the University of Toronto team led by Barbara Sherwood Lollar re‑analysed long‑term borehole records from Kidd Creek and reported consistent, low but measurable flows, while a separate 2024 Science paper documented at least 200 metric tons per year from the Bulqizë chromium mine in Albania.

These measurements show two things at once: natural H2 generation is real, and its magnitude is highly site dependent. A trillion‑ton crustal production figure is a bulk geological estimate of generation capacity rather than a claim about discrete, extractable reservoirs. Demonstrating a useful resource therefore requires three linked proofs at any site: sustained flow rates at a scale that supports collection, a recoverable concentration, and an economic path to capture and use.

Field signals: borehole flows, mine vents and the Oman stimulation

Field surveys have shifted the debate from hypothetical abundance to measurable outputs. At Kidd Creek, the team examined 35 boreholes sampled over more than a decade and found an average output of 8 kilograms of hydrogen per borehole per year. The authors extrapolated those per‑hole flows across the mine’s more than 14,000 boreholes to produce a mine‑scale figure reported as around 140 metric tons per year; the paper frames that as enough to meaningfully power local operations if capture were feasible.

Separately, a one‑kilometer experimental well in Oman received 50,000 cubic meters of injected water and, when reopened months later, emitted gas reported as 90% hydrogen. Jo Shannon presented that result at the European Geosciences Union meeting and described the well as "bubbling with gas," but she and others caution that stimulation tests raise new questions: was the gas produced by the recent injection, or did the well tap pre‑existing H2? Until full datasets—baseline chemistry, isotopes and sustained flow records—are released, the Oman result remains an important but incomplete signal.

Commercial hurdles: scaling, stimulation goals and economic uncertainty

Moving from a measured flow to a commercial operation requires scale and repeatability. ARPA‑E has funded more than a dozen projects aiming to accelerate natural H2 production, and it has set an objective to increase production rates by a factor of 10,000 compared with typical unstimulated rates—an engineering target the program uses to define commercial viability. Startups such as HyTerra and Koloma are exploring old oceanic rocks in the US Midwest and seeking pilots that could validate production and custody chains.

Even where stimulation appears promising, unanswered questions about costs and liabilities remain. The authors who released the findings have not provided the detailed stimulation protocols, long‑term production curves, or independent economic comparisons between captured geologic H2 and alternative low‑carbon supplies. Investors and operators require measured run hours, sustained flow rates and treatment costs for produced gas; absent those data, claims about commercial potential amount to assertions rather than reproducible engineering cases.

How geologic hydrogen could advance — and what could block it

The bottom line

Field studies and a small number of stimulation tests confirm that natural and high‑purity hydrogen can be present and, in some cases, made to flow. Measured outputs range from single‑digit kilograms per borehole per year up to reported mine‑scale hundreds of metric tons per year in specific cases, and a single Oman test produced gas at 90% H2 after injection. Those facts keep geologic hydrogen on the map, but they do not yet establish a repeatable, economic supply chain. Publishing full datasets, standardising stimulation protocols and publishing independent cost comparisons are the next, necessary steps before geologic hydrogen can move from intriguing geology to a deployable energy source.

What to watch

• Watch for the release of the full Oman injection datasets, including baseline gas chemistry, isotopic analyses and sustained flow rates; no date has been set.
• Watch for publication of ARPA‑E project methods, milestones and results from stimulated hydrogen trials funded to accelerate production by a factor of 10,000; no date has been set.
• Watch for any commercial well terms or production data published by HyTerra or Koloma from US pilot drilling; no date has been set.